Accuracy Evaluation of Four Blood Glucose Monitoring Systems in the Hands of Intended Users and Trained Personnel Based on ISO 15197 Requirements

Potential use of Six Sigma metrics in the quality control review of hospital glucose meters

Background and aim

This study applied Six Sigma metrics to facilitate the quality control (QC) review for hospital glucose meters.

Materials and methods

QC data from a period of six months on all hospital glucose meters were extracted from the data management system. Sigma values for each meter at two QC levels were calculated and evaluated each month by combining the imprecision, the absolute bias between the meter mean and all-meter mean, and the standards from ISO 15179:2013. The effectiveness of using Sigma values in identifying meters with possible quality problems for further Levey-Jennings QC chart review was assessed.

Results

More than 80 % of the meter's Sigma values within the six months were greater than 4 at either QC level. At the high QC level, twice as many Sigma values were below 4 than the low QC level. Including Sigma values 4, 3.5 or 3 in the criteria for the QC review reduced the number of chart review to 32.8 %, 11.2 % or 3.5 %, respectively.

Conclusions

The majority of the glucose meters examined in this study demonstrated optimal Sigma values. The Sigma metrics-based approach could be a valuable tool to guide an effective QC review of glucose meters for quality improvement.

Glukosemessung in der Diabetesdiagnostik und -therapie: Laboratoriumsmedizinische Untersuchung inkl. patientennaher Sofortdiagnostik, Blutglukoseselbstmessung und kontinuierliches Glukosemonitoring

Die Glukose-„Messlandschaft“ in Deutschland deckt viele verschiedene Einsatzzwecke und -gebiete ab. Sie reicht von hochstandardisiert messenden Laboranalysesystemen mit einem großen Gesamtportfolio von Messgrößen bis hin zu einfachen Systemen für den Patientengebrauch. Aus klinischer Sicht muss die Qualität von Glukosemessungen ausreichend hoch sein, um die vorgesehenen Zwecke, also Diagnosestellung und Verlaufskontrolle, zu erfüllen.

In der Heilkunde – also bei Messungen im Rahmen der Gesundheitsversorgung durch medizinisches Personal – definiert die Richtlinie der Bundesärztekammer zur Qualitätssicherung laboratoriumsmedizinischer Untersuchungen Vorgaben an die Qualitätssicherung. Es werden sowohl interne als auch externe (herstellerunabhängige) Qualitätskontrollen gefordert und mit spezifischen Vorgaben versehen. Diese Regelungen gelten demnach auch für alle Glukosemessungen in der Heilkunde, d. h. im Zentrallabor ebenso wie in der patientennahen Sofortdiagnostik.

Bei dem Haupteinsatzgebiet von Glukosemessungen, der Verlaufskontrolle durch Patienten mit Diabetes im Rahmen der Blutglukoseselbstmessung, fehlen i. d. R. Kontrollen der Messqualität. Für das kontinuierliche Glukosemonitoring im interstitiellen Gewebe sind Qualitätskontrollen nach dem aktuellen technischen Stand sogar überhaupt nicht möglich. Hinzu kommt, dass eine regelmäßige herstellerunabhängige Kontrolle der Messqualität nicht vorgeschrieben ist. Ziel der Arbeit ist es, einen Überblick über die unterschiedlichen Glukosemesssysteme sowie praktische Aspekte und Probleme bei der Glukosemessung zu geben.

Assessment of System Accuracy, Intermediate Measurement Precision, and Measurement Repeatability of a Blood Glucose Monitoring System Based on ISO 15197

BACKGROUND

Analytical quality of blood glucose monitoring systems (BGMS) is an important aspect for many diabetes patients. Sufficiently high analytical quality is required for adequate diabetes therapy.

METHODS

In this study, system accuracy and measurement precision of a BGMS were assessed based on ISO 15197:2013. For system accuracy, this standard requires a specific glucose distribution and at least 95% of results obtained with the BGMS in capillary blood to fall within ±15 mg/dl or ±15% (at glucose concentrations <100 mg/dl or ≥100 mg/dl, respectively) of corresponding comparison method results, and at least 99% of results to be found within clinically acceptable consensus error grid (CEG) zones A and B. Based on ISO 15197:2013, intermediate measurement precision, using control solution, and measurement repeatability, using venous blood samples, were analyzed by calculation of standard deviations (SDs) and coefficients of variation (CV) at glucose concentrations <100 mg/dl or ≥100 mg/dl, respectively, although ISO 15197:2013 does not specify acceptance criteria.

RESULTS

The BGMS fulfilled system accuracy requirements with ≥99% of results within ±15 mg/dl or ±15% of the comparison method results, and 100% of results in CEG zones A and B. Intermediate measurement precision analysis showed SD ≤2.2 mg/dl and CV ≤2.3%. Analysis of measurement repeatability showed SD ≤2.1 mg/dl and CV ≤2.4%.

CONCLUSION

System accuracy requirements of ISO 15197:2013 were fulfilled by the BGMS. As ISO 15197:2013 does not specify precision requirements, precision analysis results were compared with those reported for other BGMS in the literature and found to be similar.

The Progress of Glucose Monitoring-A Review of Invasive to Minimally and Non-Invasive Techniques, Devices and Sensors

Current glucose monitoring methods for the ever-increasing number of diabetic people around the world are invasive, painful, time-consuming, and a constant burden for the household budget. The non-invasive glucose monitoring technology overcomes these limitations, for which this topic is significantly being researched and represents an exciting and highly sought after market for many companies. This review aims to offer an up-to-date report on the leading technologies for non-invasive (NI) and minimally-invasive (MI) glucose monitoring sensors, devices currently available in the market, regulatory framework for accuracy assessment, new approaches currently under study by representative groups and developers, and algorithm types for signal enhancement and value prediction. The review also discusses the future trend of glucose detection by analyzing the usage of the different bands in the electromagnetic spectrum. The review concludes that the adoption and use of new technologies for glucose detection is unavoidable and closer to become a reality.

Accuracy of five systems for self-monitoring of blood glucose in the hands of adult lay-users and professionals applying ISO 15197:2013 accuracy criteria and potential insulin dosing errors

OBJECTIVE

In this study, accuracy in the hands of intended users was evaluated for five self-monitoring of blood glucose (SMBG) systems based on ISO 15197:2013, and possibly related insulin dosing errors were calculated. In addition, accuracy was assessed in the hands of study personnel.

METHODS

For each system (Accu-Chek ¹ Aviva Connect [A], Contour ² Next One [B], FreeStyle Freedom Lite ³ [C], GlucoMen ⁴ areo [D] and OneTouch Verio ⁵ [E]) one test strip lot was evaluated as required by ISO 15197:2013, clause 8. Number and percentage of SMBG measurements within ±15 mg/dl and ±15% of the comparison measurements at glucose concentrations <100 mg/dl and ≥100 mg/dl, respectively, were calculated. In addition, data is presented in surveillance error grids, and insulin dosing errors were modeled. The study was registered at ClinicalTrials.gov (NCT03033849).

RESULTS

Four systems (A, B, C, D) fulfilled the tested reagent system lot ISO 15197:2013 accuracy criteria with the tested reagent system lot with at least 95% (lay-users) and 99.5% (study personnel) of results within the defined limits. Measurements with all five systems were within the clinically acceptable zones of the consensus error grid and the surveillance error grid. Median modeled insulin dosing errors were between -0.8 and +0.6 units for measurements performed by lay-users and between -0.7 and +0.8 units for study personnel. Frequent lay-user errors were not checking the test strips' expiry date, applying blood incorrectly and handling the device incorrectly.

CONCLUSION

In this study, the systems showed slight differences in the number of results within ISO 15197:2013 accuracy limits. Inaccurate SMBG measurements can result in insulin dosing errors and adversely affect glycemic control.

Blood glucose meters and test strips: global market and challenges to access in low-resource settings

Blood glucose meters and test strips for self-monitoring of blood glucose (SMBG) are often inaccessible to, and infrequently used by, people with diabetes in countries with limited resources for health care. Supplies for measuring blood glucose can also be scarce in health facilities, despite being needed in a myriad of clinical settings at all levels of the health system. Numerous studies and international guidelines emphasise the value of SMBG in diabetes care, particularly in people with type 1 diabetes. In this Review, we assess global access to blood glucose meters and test strips, collating published information on cost, availability, system accuracy, competitive bidding, technological trends, and non-financial barriers. We also provide new information on global market share data and prices, taxes and tariffs, and product availability. Blood glucose meters and test strips should be viewed similarly to essential medicines, with issues of access prioritised by relevant international agencies. Efforts are needed to reduce tariffs and taxes and to create unified global system accuracy requirements and accountable post-marketing evaluations. Preferential pricing arrangements, pooled procurement, and best-purchasing practices could help to lower direct costs. SMBG supplies should also be included in national health insurance schemes. Enhanced diabetes education of health professionals and patients is crucial to ensure effective use of SMBG. Finally, as technology advances for people who can afford new interstitial fluid glucose monitoring systems, blood glucose meters and test strips must remain available and become more affordable in low-resource settings.

Evaluation of Analytical Performance of Three Blood Glucose Monitoring Systems: System Accuracy, Measurement Repeatability, and Intermediate Measurement Precision

INTRODUCTION

Blood glucose monitoring systems (BGMS) should provide sufficient analytical quality to allow adequate therapy for diabetes patients. Besides system accuracy, measurement precision is an important aspect of a BGMS' analytical quality.

METHODS

Based on ISO 15197:2013/EN ISO 15197:2015, system accuracy, measurement repeatability, and intermediate measurement precision were assessed. ISO 15197:2013 system accuracy criteria require that ⩾95% of individual BGMS' test strip lot results shall fall within ±15 mg/dl or ±15% of corresponding comparison method results (at glucose concentrations <100 mg/dl and ⩾100 mg/dl, respectively), and that ⩾99% of results fall within consensus error grid (CEG) zones A and B. Measurement repeatability was assessed using venous blood samples, whereas intermediate measurement precision was assessed using control solution samples. Standard deviation (SD) and coefficient of variation (CV) were calculated for glucose concentrations <100 mg/dl and ⩾100 mg/dl, respectively. Precision acceptance criteria are not specified by ISO 15197:2013.

RESULTS

All three BGMS fulfilled system accuracy criteria with 96% to 98% of individual test strip lot's results falling within the acceptable accuracy limits. All measurement results fell within CEG zones A and B. For measurement repeatability, SD was ⩽3.3 mg/dl, and CV was ⩽3.9% for the investigated BGMS. Assessment of intermediate measurement precision showed SD ⩽1.3 mg/dl and CV ⩽3.0%.

CONCLUSION

All three BGMS fulfilled system accuracy criteria of ISO 15197:2013. In absence of acceptance criteria, precision results were found to be consistent with the manufacturer's labeling of the investigated devices.

A Review of Blood Glucose Monitor Accuracy

The aim of this study was to assess the accuracy of blood glucose monitors (BGMs) from studies reported in the medical literature. A literature review was performed of publications between 2010 and 2017 that presented data about the accuracy of BGMs using ISO 15197 2003 and/or ISO 15197 2013 as target standards. We found 58 publications describing the performance of 143 unique BGM systems, 59 of which were Food and Drug Administration (FDA) cleared. When compared with non-FDA-cleared BGMs, FDA-cleared BGMs were significantly more likely to pass both ISO 15197 2003 (OR = 2.39, CI 1.45-3.92, P < 0.01) and ISO 15197 2013 standards (OR = 2.20, CI 1.51-3.27, P < 0.01). Newer meters were more likely to pass both ISO 15197 2003 and ISO 15197 2013 standards. Many of the studies were supported by BGM manufacturers, and when compared with independent studies, an FDA-cleared BGM was significantly more likely to pass in a manufacturer-supported study for both ISO 15197 2003 (OR = 22.4, CI 8.73-21.57, P < 0.001) and ISO 15197 2013 (OR = 23.08, CI 10.16-60.03, P < 0.001). BGM accuracy should be assessed independently following regulatory clearance to ensure accurate performance. Failure to meet performance levels mandated by standards can result in deleterious clinical and economic effects.

User Performance Evaluation of Four Blood Glucose Monitoring Systems Applying ISO 15197:2013 Accuracy Criteria and Calculation of Insulin Dosing Errors

INTRODUCTION

The international standard ISO 15197:2013 requires a user performance evaluation to assess if intended users are able to obtain accurate blood glucose measurement results with a self-monitoring of blood glucose (SMBG) system. In this study, user performance was evaluated for four SMBG systems on the basis of ISO 15197:2013, and possibly related insulin dosing errors were calculated. Additionally, accuracy was assessed in the hands of study personnel.

METHODS

Accu-Chek® Performa Connect (A), Contour® plus ONE (B), FreeStyle Optium Neo (C), and OneTouch Select® Plus (D) were evaluated with one test strip lot. After familiarization with the systems, subjects collected a capillary blood sample and performed an SMBG measurement. Study personnel observed the subjects' measurement technique. Then, study personnel performed SMBG measurements and comparison measurements. Number and percentage of SMBG measurements within ± 15 mg/dl and ± 15% of the comparison measurements at glucose concentrations < 100 and ≥ 100 mg/dl, respectively, were calculated. In addition, insulin dosing errors were modelled.

RESULTS

In the hands of lay-users three systems fulfilled ISO 15197:2013 accuracy criteria with the investigated test strip lot showing 96% (A), 100% (B), and 98% (C) of results within the defined limits. All systems fulfilled minimum accuracy criteria in the hands of study personnel [99% (A), 100% (B), 99.5% (C), 96% (D)]. Measurements with all four systems were within zones of the consensus error grid and surveillance error grid associated with no or minimal risk. Regarding calculated insulin dosing errors, all 99% ranges were between dosing errors of - 2.7 and + 1.4 units for measurements in the hands of lay-users and between - 2.5 and + 1.4 units for study personnel. Frequent lay-user errors were not checking the test strips' expiry date and applying blood incorrectly.

CONCLUSIONS

Data obtained in this study show that not all available SMBG systems complied with ISO 15197:2013 accuracy criteria when measurements were performed by lay-users.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT02916576).

FUNDING

Ascensia Diabetes Care Deutschland GmbH.

Plasma glucose and insulin responses after consumption of breakfasts with different sources of soluble fiber in type 2 diabetes patients: a randomized crossover clinical trial

Background: The amount and quality of carbohydrates are important determinants of plasma glucose after meals. Regarding fiber content, it is unclear whether the intake of soluble fibers from foods or supplements has an equally beneficial effect on lowering postprandial glucose.Objective: The aim of our study was to compare the acute effect of soluble fiber intake from foods or supplements after a common meal on postprandial plasma glucose and plasma insulin in patients with type 2 diabetes (T2D).Design: A randomized crossover clinical trial was conducted in patients with T2D. Patients consumed isocaloric breakfasts (mean ± SD: 369.8 ± 9.4 kcal) with high amounts of fiber from diet food sources (total fiber: 9.7 g; soluble fiber: 5.4 g), high amounts of soluble fiber from guar gum supplement (total fiber: 9.1 g; soluble fiber: 5.4 g), and normal amounts of fiber (total fiber: 2.4 g; soluble fiber: 0.8 g). Primary outcomes were postprandial plasma glucose and insulin (0-180 min). Data were analyzed by repeated measures ANOVA and post hoc Bonferroni test.Results: A total of 19 patients [aged 65.8 ± 7.3 y; median (IQR), 10 (5-9) y of T2D duration; glycated hemoglobin 7.0% ± 0.8%; body mass index (in kg/m²) 28.2 ± 2.9] completed 57 meal tests. After breakfast, the incremental area under the curve (iAUC) for plasma glucose [mg/dL · min; mean (95% CI)] did not differ between high fiber from diet (HFD) [7861 (6257, 9465)] and high fiber from supplement (HFS) [7847 (5605, 10,090)] (P = 1.00) and both were lower than usual fiber (UF) [9527 (7549, 11,504)] (P = 0.014 and P = 0.037, respectively). iAUCs [μIU/mL · min; mean (95% CI)] did not differ (P = 0.877): HFD [3781 (2513, 5050)], HFS [4006 (2711, 5302), and UF [4315 (3027, 5603)].Conclusions: Higher fiber intake was associated with lower postprandial glucose at breakfast, and the intake of soluble fiber from food and supplement had a similar effect in patients with T2D. This trial was registered at clinicaltrials.gov as NCT02204384.